Businesses are slumping in a Pennsylvania community that had boomed from the gas-fracking revolution

WAYNESBURG, Pa.—As fracking took off here over the past eight years, so did Gary Bowers’s business supplying everything from Gatorade to replacement valves to crews drilling into natural-gas reserves a mile underground.

This year, however, the good times at his firm, Producers Supply Co., came to a screeching halt. Since January, the company’s monthly sales have declined by more than half, as the number of drilling rigs operating in the Marcellus Shale has plummeted to 70 from 131 at the end of last year.